It's a question how "modern" you need your device to be as well. Despite being a small company, Fairphone is capable of producing fully repairable devices that are working great by my standards at least.

It's another thing engineers need to think about when designing phones, but most advances the last few years have been in terms of pointless gimmicks anyway. If they can produce phones with foldable screens, chances are they could manage replaceable batteries as well if only they wanted to.